(a) 1. Field of the Invention
The invention relates to a preservative for systems or products containing an aqueous phase, for example dyes, paints, adhesives, aqueous emulsions such as drilling oil emulsions, cooling water circulation systems, for example in air-conditioning installations, and for other products requiring a preservative including those in the washing and cleaning products sector such as apparatus rinsing liquids.
(b) 2. Information Disclosure Statement
Products containing an aqueous phase can have a tendency, due to microbial activity, to discolor, form gas, change in consistency or form odors. This is especially so if the products comprise biologically degradable substances such as emulsifiers or protective colloids which make a suitable nutrient medium for bacteria.
Preservatives containing highly chlorinated phenols or organic mercury compounds or those based on formaldehyde are seldom used nowadays because of their poor environmental safety record and toxicity to humans. The general endeavour in developing novel preservatives lies in the direction of reducing the use of chemicals while retaining the same antimicrobial activity and therefore the discovery of new synergistic combinations of active substances based on known antimicrobial substances assumes considerable importance.
EP 147,222 and EP 147,223 disclose the use of tert.-butyl hydroperoxide (TBHP), whose biostatic properties are insufficient for its use alone as a preservative, in conjunction with compounds such as xylenol, cresol, phenylphenol and alkylated phenols, as well as aldehydes, heterocyclic or quaternary compounds for the preservation of motor fuels and refrigerant lubricants, or in conjunction with a fungicide as a wood preservative. However, such mixtures no longer meet current ecological requirements.
It is known from P. Gilbert et al., Microbios 19, 125-141 (1977) and U.S. Pat. No. 3,625,904 that certain phenylglycol ethers have antimicrobial properties. French Patent 1,583,994 discloses that certain phenylglycol ethers synergistically increase the activity of phenolic and quaternary ammonium disinfectant agents.